I have a very old VBA file that was created by someone else with limited comments to explain it. The file is a training file that asks for names, and then supplies the file names you can view to train in. Variables are passed around from 5 different subroutines.
RetVal = Shell("C:\Program Files\Microsoft Office\OFFICE11\PPTVIEW.EXE  " & ProgFile, 1)
This is the line that opens the PowerPoint 4.0 files from Excel. ProgFile being a passed variable. 
My Problem: If I put the files in directory on the C:\ drive (Say C:\Training\Forklift.ppt) the file opens fine and the program does what it is supposed to do.
HOWEVER: Putting those same PPT files on my network Drive (S:\Training\Forklift.ppt) I get three error messages as pop-ups NOT coded into the program (I suspect System errors). (Path names were changed to show as S:\
- PowerPoint Viewer Cannot find the File 
RECORDS - PowerPoint Viewer Cannot find the File 
Safety - PowerPoint Viewer Cannot find the File 
Forklift.ppt 
RECORDS and Safety are NOT files being used by any of the subroutines. Is it because of the Shell Function to open PowerPoint or some other mystical thing I am overlooking? 
I am trying to rewrite the Subroutines and this is part of the unchanged code that is giving me issues.
                        
try surrounding your arg in quotes: